During a cardiac valve repair, an annuloplasty ring may be implanted as part of the valve repair to reshape the diseased valve and annulus, bringing the valve back to its natural anatomical shape. The ring also provides support to the annulus by preventing subsequent annulus dilatation once the valve has been repaired.
Annuloplasty rings are typically formed in different sizes which generally correspond to the different sizes of valve annulus from one patient to the next. In order to determine which size of annuloplasty ring to use for a particular patient, the surgeon frequently employs a sizer to approximate the current size of the valve annulus. The surgeon inserts the sizer adjacent to and in alignment with the valve annulus and visualizes whether the annulus is bigger or smaller than the sizer. This procedure may be performed several times with different sizers until a sizer which most closely corresponds to the size of the valve annulus has been determined.
As these repair procedures may be performed through small incision ports, the surgeon's ability to visualize the surrounding anatomy is often limited. The nature of the location of the valve repair as well as the small size of the anatomy and repair items makes it difficult for a surgeon to easily guide and place objects, such as annuloplasty rings and annulus sizers, within the patient for measurement and implantation. Furthermore, the small size of such objects poses a potential threat to the patient, as such objects may be mishandled, misplaced, or lost in the patient due to error on the part of the surgeon and/or the robot performing the surgical procedure.
Therefore, a need exists for a device for sizing a heart valve annulus that allows a surgeon greater and more accurate control over the surgical procedure and that provides a safety means for recovering a misplaced or lost device within the patient.